Recent Study Finds Tripling in Thyroid Cancer

According to a recent report by Davies and Welch,1 the incidence of thyroid cancer in the United States has nearly tripled since 1975, from 4.9 to 14.3 per 100,000 persons, with most of the increase due to papillary thyroid cancer, which has increased from 3.4 to 12.5 per 100,000 persons. The researchers had previously reported a doubling in thyroid cancer incidence, largely due to the detection of small papillary cancers, and they conducted the current study to determine whether the incidence had stabilized.

They used data from the Surveillance, Epidemiology, and End Results (SEER) program and the National Vital Statistics System to analyze trends from 1975 to 2009, finding a relative rate of 2.9 for the general incidence and 3.7 for papillary thyroid cancers. The absolute increase in women, from 6.5 to 21.4 per 100,000 women, was almost four times greater than that of men (from 3.1 to 6.9 per 100,000 men). They found the mortality rate, however, to be stable at approximately 0.5 deaths per 100,000.

Davies and Welch concluded, “this is not an epidemic of disease but rather an epidemic of diagnosis. The problem is particularly acute for women, who have lower autopsy prevalence of thyroid cancer than men but higher cancer detection rates by a 3:1 ratio.” ■